Apparatus and methods for overload protection of radio frequency amplifiers

ABSTRACT

Radio frequency (RF) amplifiers with overload protection are provided herein. In certain configurations, an RF amplifier system includes an RF amplifier that receives an RF signal from an input terminal. The RF amplifier includes an amplification field-effect transistor (FET) having a gate that receives the RF signal, and a degeneration circuit connected between a source of the amplifier FET and a ground voltage. The RF amplifier system further includes an electrostatic discharge protection circuit including a plurality of protection diodes electrically connected in series between the input terminal and the ground voltage, and a detector having an input connected along an electrical path through the plurality of protection diodes and an output that generates a detection signal operable to control an amount of degeneration provided by the degeneration circuit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/682,529, filed Nov. 13, 2019 and titled “APPARATUS AND METHODS FOROVERLOAD PROTECTION OF RADIO FREQUENCY AMPLIFIERS,” which is acontinuation of U.S. application Ser. No. 15/941,554, filed Mar. 30,2018 and titled “APPARATUS AND METHODS FOR OVERLOAD PROTECTION OF RADIOFREQUENCY AMPLIFIERS,” which claims the benefit of priority under 35U.S.C. § 119 of U.S. Provisional Patent Application No. 62/484,073,filed Apr. 11, 2017 and titled “APPARATUS AND METHODS FOR OVERLOADPROTECTION OF RADIO FREQUENCY AMPLIFIERS,” each of which is hereinincorporated by reference in its entirety.

BACKGROUND Field

Embodiments of the invention relate to electronic systems, and inparticular, to radio frequency (RF) electronics.

Description of Related Technology

An RF amplifier is used to boost or amplify an RF signal. Thereafter,the amplified RF signal can be used for a variety of purposes,including, for example, driving a switch, a mixer and/or a filter in anRF communication system. RF amplifiers can amplify signals of a widerange of frequencies, for instance, signals in a frequency range ofabout 30 kHz to 300 GHz, such as in the range of about 450 MHz to about6 GHz for certain communications standards.

One example of an RF amplifier is a low noise amplifier (LNA), which canbe used to amplify a relatively weak RF signal received over an antenna.

SUMMARY

In certain embodiments, the present disclosure relates to a radiofrequency amplifier system. The radio frequency amplifier systemincludes an input terminal configured to receive a radio frequencysignal, an output terminal, a radio frequency amplifier configured toreceive the radio frequency signal from the input terminal and togenerate an amplified radio frequency signal at the output terminal, andan overload detection circuit configured to generate a detection signalindicating a detected signal level of the radio frequency amplifier. Theradio frequency amplifier includes an amplification device configured toamplify the radio frequency signal and a degeneration circuit configuredto provide degeneration to the amplification device. The detectionsignal is operable to control an amount of degeneration provided by thedegeneration circuit so as to protect the radio frequency amplifier fromoverload.

In various embodiments, the radio frequency amplifier system furtherincludes an electrostatic discharge protection circuit electricallycoupled to the input terminal and configured to protect the radiofrequency amplifier from an electrostatic discharge event, and theoverload detection circuit is integrated with the electrostaticdischarge protection circuit. According to a number of embodiments, theoverload detection circuit is configured to generate the detectionsignal based on an internal signal level of the electrostatic dischargeprotection circuit. In accordance with several embodiments, theelectrostatic discharge protection circuit includes a plurality ofdiodes in series, and the overload detection circuit is configured togenerate the detection signal based on a voltage across one or more ofthe plurality of diodes. According to several embodiments, the overloaddetection circuit includes a reference current source configured togenerate a reference current, and the overload detection circuit isconfigured to generate the detection signal based on an amount of thereference current steered to the electrostatic discharge protectioncircuit.

In some embodiments, the radio frequency amplifier is a low noiseamplifier.

In several embodiments, the amplification device includes a bipolartransistor, and the degeneration circuit configured to provide emitterdegeneration to the bipolar transistor.

In various embodiments, the amplification device includes a field-effecttransistor, the degeneration circuit configured to provide sourcedegeneration to the field-effect transistor.

In a number of embodiments, the degeneration circuit includes aninductor, and the detection signal is operable to control an amount ofdegeneration inductance provided by the degeneration circuit.

In several embodiments, the degeneration circuit includes a resistor,and the detection signal is operable to control an amount ofdegeneration resistance provided by the degeneration circuit.

In a number of embodiments, the detection signal is operable to increasethe amount of degeneration provided by the degeneration circuit inresponse to the overload detection circuit detecting overload.

In various embodiments, the degeneration circuit includes a switch and acontrol buffer configured to control the switch based on the detectionsignal. In accordance with several embodiments, the control buffer ispowered in part by the detection signal. According to some embodiments,the control buffer is configured to receive a digital control signalconfigured to control the switch.

In certain embodiments, the present disclosure relates to a packagedmodule. The package module includes a packaging substrate and asemiconductor die attached to the packaging substrate. The semiconductordie includes an input terminal and a radio frequency amplifierconfigured to receive a radio frequency signal from the input terminal.The radio frequency amplifier includes an amplification deviceconfigured to amplify the radio frequency signal and a degenerationcircuit configured to provide degeneration to the amplification device.The semiconductor die further includes an overload detection circuitconfigured to generate a detection signal indicating a detected signallevel of the radio frequency amplifier, and the detection signal isoperable to control an amount of degeneration provided by thedegeneration circuit so as to protect the radio frequency amplifier fromoverload.

In several embodiments, the integrated circuit further includes anelectrostatic discharge protection circuit electrically coupled to theinput terminal and configured to provide protection against anelectrostatic discharge event, and the overload detection circuit isintegrated with the electrostatic discharge protection circuit.According to a number of embodiments, the overload detection circuit isconfigured to generate the detection signal based on an internal signallevel of the electrostatic discharge protection circuit. In accordancewith some embodiments, the electrostatic discharge protection circuitincludes a plurality of diodes in series, and the overload detectioncircuit is configured to generate the detection signal based on avoltage across one or more of the plurality of diodes. According tovarious embodiments, the overload detection circuit includes a referencecurrent source configured to generate a reference current, and theoverload detection circuit is configured to generate the detectionsignal based on an amount of the reference current steered to theelectrostatic discharge protection circuit.

In some embodiments, the radio frequency amplifier is a low noiseamplifier.

In various embodiments, the amplification device includes a bipolartransistor, and the degeneration circuit configured to provide emitterdegeneration to the bipolar transistor.

In a number of embodiments, the degeneration circuit includes a switchand a control buffer configured to control the switch based on thedetection signal. In accordance with several embodiments, the controlbuffer is powered in part by the detection signal. According to variousembodiments, the control buffer is configured to receive a digitalcontrol signal configured to control the switch.

In some embodiments, the amplification device includes a field-effecttransistor, and the degeneration circuit configured to provide sourcedegeneration to the field-effect transistor.

In various embodiments, the degeneration circuit includes an inductor,and the detection signal is operable to control an amount ofdegeneration inductance provided by the degeneration circuit.

In a number of embodiments, the degeneration circuit includes aresistor, and the detection signal operable to control an amount ofdegeneration resistance provided by the degeneration circuit.

In several embodiments, the detection signal is operable to increase theamount of degeneration provided by the degeneration circuit in responseto the overload detection circuit detecting an overload condition of theradio frequency amplifier.

In certain embodiments, the present disclosure relates to a method ofoverload protection in a radio frequency amplifier system. The methodincludes receiving a radio frequency signal at an input terminal of aradio frequency amplifier, amplifying the radio frequency signal usingan amplification device of the radio frequency amplifier, providingdegeneration to the amplification device using a degeneration circuit ofthe radio frequency amplifier, generating a detection signal indicated adetected signal level of the radio frequency amplifier using an overloaddetection circuit, and protecting the radio frequency amplifier fromoverload by controlling an amount of degeneration provided by thedegeneration circuit based on the detection signal.

In some embodiments, the method further includes providing electrostaticdischarge protection to the input terminal using an electrostaticdischarge protection circuit, and generating the detection signal basedon an internal signal level of the electrostatic discharge protectioncircuit.

In several embodiments, the method further includes increasing theamount of degeneration using the detection signal in response todetermining that the detected signal level indicates overload.

In a number of embodiments, providing degeneration to the amplificationdevice includes providing emitter degeneration to a bipolar transistor.

In various embodiments, providing degeneration to the amplificationdevice includes providing source degeneration to a field-effecttransistor.

In some embodiments, providing degeneration to the amplification deviceincludes providing inductive degeneration using an inductor.

In several embodiments, providing degeneration to the amplificationdevice includes providing resistive degeneration using a resistor.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of this disclosure will now be described, by way ofnon-limiting example, with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a radio frequency (RF) amplifier systemaccording to one embodiment.

FIG. 2 is a schematic diagram of an RF amplifier system according toanother embodiment.

FIG. 3A is a schematic diagram of an RF amplifier system according toanother embodiment.

FIG. 3B is a schematic diagram of an RF amplifier system according toanother embodiment.

FIG. 3C is a schematic diagram of an RF amplifier system according toanother embodiment.

FIG. 3D is a schematic diagram of an RF amplifier system according toanother embodiment.

FIG. 3E is a schematic diagram of an RF amplifier system according toanother embodiment.

FIG. 4 is a schematic diagram of an RF amplifier system according toanother embodiment.

FIG. 5 is a schematic diagram of an RF amplifier system according toanother embodiment.

FIG. 6 is a schematic diagram of one embodiment of a control buffer fora degeneration circuit.

FIG. 7A is a schematic diagram of one embodiment of a packaged module.

FIG. 7B is a schematic diagram of a cross-section of the packaged moduleof FIG. 7A taken along the lines 7B-7B.

FIG. 8A is a schematic diagram of a front end system according to oneembodiment.

FIG. 8B is a schematic diagram of a front end system according toanother embodiment.

FIG. 9A is a schematic diagram of a wireless communication deviceaccording to one embodiment.

FIG. 9B is a schematic diagram of a wireless communication deviceaccording to another embodiment.

FIG. 9C is a schematic diagram of another example of a wirelesscommunication device.

FIG. 10 is a schematic diagram of one example of an Internet of things(IoT) network.

FIG. 11A is a schematic diagram of one example of an IoT-enabled watch.

FIG. 11B is a schematic diagram of one example of a front end system foran IoT-enabled object.

FIG. 12A is a schematic diagram of one example of IoT-enabled industrialequipment.

FIG. 12B is a schematic diagram of another example of a front end systemfor an IoT-enabled object.

FIG. 13A is a schematic diagram of one example of an IoT-enabled lock.

FIG. 13B is a schematic diagram of one example of a circuit board forthe IoT-enabled lock of FIG. 13A.

FIG. 14A is a schematic diagram of one example of an IoT-enabledthermostat.

FIG. 14B is a schematic diagram of one example of a circuit board forthe IoT-enabled thermostat of FIG. 14A.

FIG. 15A is a schematic diagram of one example of IoT-enabled light.

FIG. 15B is a schematic diagram of one example of a circuit board forthe IoT-enabled light of FIG. 15A.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The following detailed description of certain embodiments presentsvarious descriptions of specific embodiments. However, the innovationsdescribed herein can be embodied in a multitude of different ways, forexample, as defined and covered by the claims. In this description,reference is made to the drawings where like reference numerals canindicate identical or functionally similar elements. It will beunderstood that elements illustrated in the figures are not necessarilydrawn to scale. Moreover, it will be understood that certain embodimentscan include more elements than illustrated in a drawing and/or a subsetof the elements illustrated in a drawing. Further, some embodiments canincorporate any suitable combination of features from two or moredrawings.

Absent an overdrive protection scheme, providing a large input signal toan RF amplifier can result in high current and/or voltage manifesting incircuitry of the RF amplifier, such as amplification transistors. Suchhigh current and/or voltage can cause permanent electrical overstressdamage to the amplification transistors such that they are inoperable orthat their operation is impaired.

There is a need for improved RF amplifier systems, such as low noiseamplifier (LNA) systems, in which amplification transistors areprotected from overdrive conditions arising from large input signals.

Apparatus and methods for overload protection of RF amplifiers areprovided herein. In certain configurations, an RF amplifier systemincludes an RF amplifier that receives an RF signal from an inputterminal and that generates an amplified RF signal at an outputterminal, and an overload detection circuit that generates a detectionsignal indicating a detected signal level of the RF amplifier. The RFamplifier includes an amplification device that amplifies the RF signaland a degeneration circuit that provides degeneration to theamplification device. Additionally, the detection signal is operable tocontrol an amount of degeneration provided by the degeneration circuitso as to protect the RF amplifier from overload.

The overload protection schemes herein can be used to limit largecurrent and/or voltage swing conditions manifesting within circuitry ofan RF amplifier, such as an LNA.

In certain implementations, the overload detection circuit adjusts anamount of degeneration provided by the degeneration circuit from a firstdegeneration amount to a second degeneration amount in response todetecting an overload condition. However, the teachings herein areapplicable to overload detection circuits implemented in a wide varietyof ways, including, but not limited to, overload detection circuits thatcontrol the amount of degeneration between two or more discrete levelsas well as overload detection circuits that provide analog adjustment tothe amount of degeneration.

The overload protection schemes disclosed herein are applicable to awide variety of RF communication systems, including, but not limited to,smartphones, base stations, handsets, wearable electronics, and/ortablets.

FIG. 1 is a schematic diagram of an RF amplifier system 10 according toone embodiment. The RF amplifier system 10 includes an input terminalRF_(IN), an output terminal RF_(OUT), an RF amplifier 1, and an overloaddetection circuit 2. As shown in FIG. 1, the overload detection circuit2 includes an amplification or transconductance (g_(m)) device 3 and adegeneration circuit 4.

Although the RF amplifier system 10 of FIG. 1 illustrates oneimplementation of an RF amplifier system with overload protection, theteachings herein are applicable to RF amplifier systems implemented in awide variety of ways.

During operation of the RF amplifier system 10, the RF amplifier 1receives an RF signal from the input terminal RF_(IN). Additionally, theamplification device 3 amplifies the RF input signal to generate anamplified RF signal at the output terminal RF_(OUT). In one embodiment,the RF amplifier 1 is an LNA, and the RF signal corresponds to a signalreceived from an antenna.

Although, the RF amplifier 1 is illustrated as including a singleamplification device, the teachings herein are applicable toconfigurations using multiple transistors. In one example, an RFamplifier includes an amplification device, such as a common emittertransistor or common source transistor, and a cascode device, such as acommon base transistor or common gate transistor. Furthermore, althoughthe RF amplifier 1 is illustrated as including a single stage, theteachings herein are applicable to multi-stage amplifiers.

The amplification device 3 can be implemented in a variety of ways. Inone example, the amplification device 3 is implemented as a commonemitter transistor. In another example, the amplification device 3 isimplemented as a common source transistor. The RF amplifier 1 caninclude one or more bipolar transistors, one or more field-effecttransistors (FETs), or a combination thereof.

As shown in FIG. 1, the amplification device 3 is electrically connectedin series with the degeneration circuit 4. In certain implementations,the amplification device 3 and the degeneration circuit 4 areelectrically connected in series between the output terminal RF_(OUT)and a DC voltage, such as ground.

The degeneration circuit 4 can be implemented in a wide variety of ways,such as by using resistors and/or inductors. In one example, theamplification device 3 is implemented as a bipolar transistor, and thedegeneration circuit 4 provides emitter degeneration to the bipolartransistor. In another example, the amplification device 3 isimplemented as a FET, and the degeneration circuit 4 provides sourcedegeneration to the FET.

Including the degeneration circuit 4 provides a number of advantages.For example, the degeneration circuit 4 can improve input impedancematching, enhance stability, and/or increase the RF amplifier'slinearity.

In the illustrated embodiment, the overload detection circuit 2 iselectrically coupled to the input terminal RF_(IN). Additionally, theoverload detection circuit 2 generates a detection signal indicating adetected signal level of the RF amplifier 1. The overload detectioncircuit 2 provides the detection signal to the degeneration circuit 4,and the detection signal operates to control an amount of degenerationprovided by the degeneration circuit 4 to protect the RF amplifier 1from overload.

In certain implementations, in response to detecting an overloadcondition, the overload detection circuit 2 increases the impedance ofthe degeneration circuit 4. By increasing the amount of degradationimpedance, the bias of the amplification device 3 is cut off and/or again of the amplification device 3 is reduced.

FIG. 2 is a schematic diagram of an RF amplifier system 20 according toanother embodiment. The RF amplifier system 20 includes an inputterminal RF_(IN), an output terminal RF_(OUT), an RF amplifier 1, and anelectrostatic discharge (ESD) protection circuit 11 that includes anoverload detection circuit 12.

The RF amplifier system 20 of FIG. 2 is similar to the RF amplifiersystem 10 of FIG. 1, except that the RF amplifier system 20 of FIG. 2includes an overload detection circuit that is integrated as part of anESD protection circuit.

ESD events can arise from a variety of sources, such as external chargesources, supply switching, and/or electromagnetic pulses, and areassociated with high levels of power and/or charge. An ESD event cancause charge build-up in an integrated circuit (IC), leading to highvoltage and/or current levels beyond which the IC can reliably tolerate.Absent a protection mechanism, the ESD event can lead to IC damage, suchas gate oxide rupture, junction breakdown, and/or metal damage.

An IC's robustness to ESD events can be evaluated in a wide variety ofways. For example, specifications for ESD compliance can be set byvarious organizations, such as the International ElectrotechnicalCommission (IEC) and/or Joint Electronic Device Engineering Council(JEDEC). For instance, a human body model (HBM) test can be used toevaluate the IC's performance with respect to ESD events arising fromthe sudden release of electrostatic charge from a person to an IC. AnIC's performance with respect to such specifications can be an importantperformance metric by which the IC is evaluated.

In the illustrated embodiment, the overload detection circuit 12 isintegrated with the ESD protection circuit 11. Accordingly, devices usedfor providing ESD protection, such as diodes, silicon-controlledrectifiers, and/or transistors are also used in part for detecting thesignal level of the RF amplifier 1.

Integrating the overload detection circuit 12 with the ESD protectioncircuit 11 can provide a number of advantages. For example, implementingan overload detection circuit 12 in this manner can reduce componentcount, size, cost, and/or an amount of parasitic loading of the inputterminal RF_(IN) relative to an implementation including a separate ESDprotection circuit and a separate overload detection circuit.

FIG. 3A is a schematic diagram of an RF amplifier system 50 according toanother embodiment. The RF amplifier system 50 includes an inputterminal RF_(IN), an output terminal RF_(OUT), an RF amplifier 1, and anESD protection circuit 31.

The RF amplifier system 50 of FIG. 3A is similar to the RF amplifiersystem 20 of FIG. 2, except that the RF amplifier system 50 of FIG. 3Aillustrates a specific implementation of an ESD protection circuit withintegrated overload detection.

For example, the illustrated ESD protection circuit 31 includes a firststring or series combination of diodes 35 a-35 c and a second string ofdiodes 36 a-36 c. In the illustrated embodiment, the first string ofdiodes 35 a-35 c includes three diodes connected in series from anode tocathode between ground (GND) and the input terminal RF_(IN).Additionally, the second string of diodes 36 a-36 c includes threediodes connected in series from anode to cathode between the inputterminal RF_(IN) and ground.

The first string of diodes 35 a-35 c provides protection against anegative polarity ESD event that causes a voltage of the input terminalRF_(IN) to decrease below ground. Additionally, a number of and/or aforward voltage of the diodes 35 a-35 c can control a trigger voltage atwhich the first string of diodes 35 a-35 c conducts. Although an examplewith three diodes is shown, ESD protection can be provided using more orfewer diodes and/or using other types of ESD protection devices.

The second string of diodes 36 a-36 c provides protection against apositive polarity ESD event that causes a voltage of the input terminalRF_(IN) to increase above ground. Additionally, a number of and/or aforward voltage of the diodes 36 a-36 c can control a trigger voltage atwhich the second string of diodes 36 a-36 c conducts. Although anexample with three diodes is shown, ESD protection can be provided usingmore or fewer diodes and/or using other types of ESD protection devices.

In the illustrated embodiment, the ESD protection circuit 31 furtherincludes a detector 42 that generates a detection signal based on aninternal signal level of the ESD protection circuit. For example, inthis embodiment, the detector 42 controls the detection signal based ona voltage across the ESD protection diode 35 a.

Although one embodiment of an ESD protection circuit with integratedoverload detection is shown in FIG. 3A, other implementations arepossible. For example, an ESD protection circuit with integratedoverload detection can be implemented in a wide variety of ways. Inanother embodiment, a detector controls a detection signal based on avoltage of an ESD protection transistor. In yet another embodiment, adetector controls a detection signal based on a voltage of a siliconcontrolled rectifier.

Integrating an overload detection circuit as part of an ESD protectioncircuit can provide a number of advantages. For example, implementing anoverload detection circuit in this manner can reduce component count,size, cost, and/or an amount of parasitic loading of the input terminalRF_(IN) relatively to an implementation including a separate ESDprotection circuit and overload detection circuit.

FIG. 3B is a schematic diagram of an RF amplifier system 80 according toanother embodiment. The RF amplifier system 80 includes an inputterminal RF_(IN), an output terminal RF_(OUT), an RF amplifier 1, and anESD protection circuit 51. The ESD protection circuit 51 includes afirst string of diodes 35 a-35 c, a second string of diodes 36 a-36 c,and a detector 62.

The RF amplifier system 80 of FIG. 3B is similar to the RF amplifiersystem 50 of FIG. 3A, except that the RF amplifier system 80 illustratesa specific implementation of the detector 42 of FIG. 3A.

For example, the detector 62 of FIG. 3B includes a reference currentsource (implemented in this embodiment as a PFET 71 with a gate biasvoltage V_(B)), an NFET 72, a first diode 73, a second diode 74, and acapacitor 78.

When an overload condition is not present at the input terminal RF_(IN),a voltage across the ESD protection diode 35 a is relatively small (forexample, about 0 V), and the PFET 71 controls the detection signal to ahigh level (for example, about VDD). However, when an overload conditionis present at the input terminal RF_(IN), the voltage across the ESDprotection diode 35 a is sufficient to turn on the NFET 72.Additionally, activation of the NFET 72 results in a greater currentflowing through the NFET 72 relative to the PFET 71, thereby pulling thedetection signal to a low level. Accordingly, in this embodiment, a highvalue of the detection signal indicates no overload being present, and alow value of the detection signal indicates overload. However, otherimplementations are possible.

Although one implementation of an ESD protection circuit with anintegrated overload detection circuit is shown in FIG. 3B, otherimplementations are possible. For example, an ESD protection circuitwith integrated overload detection circuit can be implemented in a widevariety of ways.

FIG. 3C is a schematic diagram of an RF amplifier system 90 according toanother embodiment. The RF amplifier system 90 includes an inputterminal RF_(IN), an output terminal RF_(OUT), an RF amplifier 1, and anESD protection circuit 81.

The RF amplifier system 90 of FIG. 3C is similar to the RF amplifiersystem 50 of FIG. 3A, except that the RF amplifier system 90 illustratesan implementation in which the input of detector 42 is coupled to acathode of the second diode 35 b, rather than to the cathode of thefirst diode 35 a.

The RF amplifier system 90 illustrates another example of detecting foroverload based on monitoring an internal signal level of the ESDprotection circuit. However, other implementations are possible.

FIG. 3D is a schematic diagram of an RF amplifier system 100 accordingto another embodiment. The RF amplifier system 100 includes an inputterminal RF_(IN), an output terminal RF_(OUT), an RF amplifier 1, an ESDprotection circuit 31, and an input matching circuit 91.

The RF amplifier system 100 of FIG. 3D is similar to the RF amplifiersystem 50 of FIG. 3A, except that the RF amplifier system 100 furtherincludes the input matching circuit 91.

During operation of the RF amplifier 1, a voltage gain is providedacross the input matching circuit 91. The voltage gain aids the detector42 in generating a detection signal indicative of overload. Accordingly,including the input matching circuit 91 enhances the performance of thedetector 42.

FIG. 3E is a schematic diagram of an RF amplifier system 110 accordingto another embodiment. The RF amplifier system 110 includes an inputterminal RF_(IN), an output terminal RF_(OUT), an RF amplifier 1, an ESDprotection circuit 31, and an input matching inductor 101.

The RF amplifier system 110 of FIG. 3E is similar to the RF amplifiersystem 100 of FIG. 3D, except that the RF amplifier system 110 of FIG.3E illustrates a specific implementation of an input matching circuit.In particular, the RF amplifier system 110 of FIG. 3E includes the inputmatching inductor 101.

When an overload condition is received at the input terminal RF_(IN), avoltage gain is provided across the input matching inductor 101, therebyreducing a delay of the detector 42 in generating a detection signalindicating presence of overload. Decreasing the delay of the detector 42in turn results in faster adjustment of the degeneration circuit 4 and acorresponding enhancement in protection against damage from overload.

FIG. 4 is a schematic diagram of an RF amplifier system 160 according toanother embodiment. The RF amplifier system 160 includes an inputterminal RF_(IN), an output terminal RF_(OUT), an RF amplifier 131, andan ESD protection circuit 11 that includes an overload detection circuit12.

The RF amplifier system 160 of FIG. 4 is similar to the RF amplifiersystem 20 of FIG. 2, except that the RF amplifier system 160 illustratesa specific implementation of an RF amplifier.

For example, the RF amplifier 131 of FIG. 4 includes an amplificationFET 133, an input DC blocking capacitor 135, an input bias circuit 141,an output bias circuit 142, and a degeneration circuit 134, which hasadjustable degeneration. The degeneration circuit 134 includes adegeneration inductor 151, a switch 152 (for instance, a FET switch), aresistor 153, and a control buffer 154. Although one embodiment of an RFamplifier and degeneration circuit is shown in FIG. 4, the teachingsherein are applicable to RF amplifiers and degeneration circuitsimplemented in a wide variety of ways.

In the illustrated embodiment, the control buffer 154 includes an inputthat receives a digital enable signal EN and a power supply input thatreceives the detector signal from the overload detection circuit 12 ofthe ESD protection circuit 11. Additionally, the output of the controlbuffer 154 is provided to the switch 152 via the resistor 153.

The signal values of the detection signal and the digital enable signalcontrol activation of the switch 152, thereby controlling an amount ofdegeneration provided by the degeneration circuit 134.

The degeneration circuit 134 of FIG. 4 includes the control buffer 154,which aids in providing digital control over enabling the RF amplifier131 while also aiding the overload detection circuit 12 in controllingan amount of degeneration provided by the degeneration circuit 134. Incertain implementations, the detection signal is used at least in partto power the control buffer 154. Thus, in this embodiment when thedetection signal goes low to indicate overload, the output of thecontrol buffer 154 is controlled to turn off the switch 152 and increasethe amount of degeneration provided by the degeneration circuit 134.

Including the control buffer 154 can increase signal swing range,enhance a speed at which the detection signal can adjust degeneration,and/or enhance flexibility by also providing control over the amount ofdegeneration via one or more digital control signals. However, otherimplementations are possible.

Although the RF amplifier 131 of FIG. 4 is implemented using inductivedegeneration, the teachings herein are also applicable to RF amplifiersusing resistive degeneration, or a combination of inductive andresistive degeneration.

FIG. 5 is a schematic diagram of an RF amplifier system 180 according toanother embodiment. The RF amplifier system 180 includes an inputterminal RF_(IN), an output terminal RF_(OUT), an RF amplifier 161, andan ESD protection circuit 11 that includes an overload detection circuit12. The RF amplifier 161 includes an amplification FET 133, an input DCblocking capacitor 135, an input bias circuit 141, an output biascircuit 142, and a degeneration circuit 164 that includes a degenerationresistor 171, a switch 152, a resistor 153, and a control buffer 154.

The RF amplifier system 180 of FIG. 5 is similar to the RF amplifiersystem 160 of FIG. 4, except that the RF amplifier system 180illustrates an implementation using resistive degeneration ratherinductive degeneration.

FIG. 6 is a schematic diagram of one embodiment of a control buffer 300for a degeneration circuit. The control buffer 300 includes a firstinverter NFET 301, a first inverter PFET 311, a second inverter NFET302, a second inverter PFET 312, and a feedback NFET 321.

The control buffer 300 includes a first inverter (also referred toherein as a digital inverter circuit) associated with the first inverterNFET 301 and the first inverter PFET 311, and a second inverterassociated with the second inverter NFET 302 and the second inverterPFET 312. The first inverter is powered by a supply voltage VDD, and thesecond inverter is powered by the detection signal DET.

In the illustrated embodiment, a high level of the detection signal DETindicates no overload, and a low level of the detection signal DETindicates overload. Thus, during normal operation of an RF amplifierwhen no overload is present, the output OUT of the control buffer 300 iscontrolled based on a state of the digital enable signal EN. However,when an overload condition is present, the detection signal DET ispulled low, and the output OUT is controlled low regardless of the stateof the digital enable signal EN.

The illustrated control buffer 300 also includes the feedback NFET 321,which serves to provide hysteresis, thereby enhancing stability of theoutput OUT.

Although one embodiment of a control buffer is shown in FIG. 6, theteachings herein are applicable to degeneration circuits includingcontrol buffers implemented in other ways as well as to implementationsof degeneration circuits omitting a control buffer.

FIG. 7A is a schematic diagram of one embodiment of a packaged module500. FIG. 7B is a schematic diagram of a cross-section of the packagedmodule 500 of FIG. 7A taken along the lines 7B-7B.

The packaged module 500 includes radio frequency components 501, asemiconductor die 502, surface mount devices 503, wirebonds 508, apackage substrate 520, and encapsulation structure 540. The packagesubstrate 520 includes pads 506 formed from conductors disposed therein.Additionally, the semiconductor die 502 includes pins or pads 504, andthe wirebonds 508 have been used to connect the pads 504 of the die 502to the pads 506 of the package substrate 520.

The semiconductor die 502 includes an RF amplifier 1 and an overloaddetection circuit 2. The RF amplifier 1 includes an amplification devicethat amplifies an RF signal and a degeneration circuit that providesdegeneration to the amplification device. Additionally, the detectioncircuit 2 generates a detection signal that is operable to control anamount of degeneration provided by the degeneration circuit so as toprotect the RF amplifier 1 from overload. In certain implementations,the RF amplifier 1 is an LNA.

The packaging substrate 520 can be configured to receive a plurality ofcomponents such as the semiconductor die 502 and the surface mountdevices 503, which can include, for example, surface mount capacitorsand/or inductors. In one implementation, the radio frequency components501 include integrated passive devices (IPDs).

As shown in FIG. 7B, the packaged module 500 is shown to include aplurality of contact pads 532 disposed on the side of the packagedmodule 500 opposite the side used to mount the semiconductor die 502.Configuring the packaged module 500 in this manner can aid in connectingthe packaged module 500 to a circuit board, such as a phone board of awireless device. The example contact pads 532 can be configured toprovide radio frequency signals, bias signals, and/or power (forexample, a power supply voltage and ground) to the semiconductor die 502and/or the surface mount devices 503. As shown in FIG. 7B, theelectrical connections between the contact pads 532 and thesemiconductor die 502 can be facilitated by connections 533 through thepackage substrate 520. The connections 533 can represent electricalpaths formed through the package substrate 520, such as connectionsassociated with vias and conductors of a multilayer laminated packagesubstrate.

In some embodiments, the packaged module 500 can also include one ormore packaging structures to, for example, provide protection and/orfacilitate handling. Such a packaging structure can include overmold orencapsulation structure 540 formed over the packaging substrate 520 andthe components and die(s) disposed thereon.

It will be understood that although the packaged module 500 is describedin the context of electrical connections based on wirebonds, one or morefeatures of the present disclosure can also be implemented in otherpackaging configurations, including, for example, flip-chipconfigurations.

An RF front end system can include circuits in a signal path between anantennas and a baseband system. Some RF front ends can include circuitsin signal paths between one or more antennas and a mixer configured tomodulate a signal to RF or to demodulate an RF signal.

FIG. 8A is a schematic diagram of a front end system 630 according toone embodiment.

The RF front end system 630 is configured to receive RF signals from anantenna 641 and to transmit RF signals by way of the antenna 641. Theillustrated front end system 630 includes a first multi-throw switch642, a second multi-throw switch 643, a receive signal path thatincludes an LNA 646, a bypass network 644, and a transmit signal paththat includes a power amplifier 645. The RF front end system 630 caninclude one or more RF amplifiers implemented in accordance with theteachings herein. For instance, in one example, the LNA 646 isimplemented in accordance with any of the principles and advantagesdiscussed herein.

The bypass network 644 can include any suitable network for matchingand/or bypassing the receive signal path and the transmit signal path.The bypass network 644 can be implemented by a passive impedance networkor by a conductive trace or wire. The power amplifier 645 can beimplemented in a wide variety of ways.

The first multi-throw switch 642 can selectively connect a particularsignal path to the antenna 641. The first multi-throw switch 642 canelectrically connect the receive signal path to the antenna 641 in afirst state, electrically connect the bypass signal path to the antenna641 in a second state, and electrically connect the transmit signal pathto the antenna 641 in a third state.

The second multi-throw switch 643 can selectively connect a particularsignal path to an input/output port of the front end system 630, inwhich the particular signal path is the same signal path electricallyconnected to the antenna 641 by way of the first multi-throw switch 642.Accordingly, the second multi-throw switch 643 together with the firstmulti-throw switch 642 can selectively connect a particular signal pathbetween the antenna 641 and the input/output port of the front endsystem 630.

The control and biasing circuit 647 can be used to control and biascircuitry of the RF front end system 630, including, but not limited to,the LNA 646, the first multi-throw switch 641, and/or the secondmulti-throw switch 643.

FIG. 8B is a schematic diagram of a front end system 640 according toanother embodiment.

The RF front end system 640 of FIG. 8B is similar to the RF front endsystem 630 of FIG. 8A, except that the first multi-throw switch 649 isconfigured to selectively connect a particular signal path to either afirst antenna 641 or a second antenna 648. The multi-throw switch 649can be a multi-throw, multi-pole switch.

The front end systems of FIGS. 8A and/or 8B can be implemented in apackaged module. Such packaged modules can include relatively low costlaminate-based front end modules that combine low noise amplifiers withpower amplifiers and/or switch functions. Some such packaged modules canbe multi-chip modules. In certain implementations, some or the all ofthe illustrated components in any of the front end systems in FIGS. 8Aand/or 8B can be embodied on a single integrated circuit or die. Such adie can be manufactured using any suitable process technology. As oneexample, the die can be a semiconductor-on-insulator die, such as asilicon-on-insulator (SOI) die. According to some implementations, oneor more antennas can be integrated with any of the front end systemsdiscussed herein.

FIGS. 9A and 9B are schematic block diagrams of illustrative wirelesscommunication devices that include an RF amplifier and/or a front endsystem in accordance with one or more embodiments. The wirelesscommunication devices can be any suitable wireless communication device.For instance, this device can be a mobile phone, such as a smart phone.

FIG. 9A is a schematic diagram of a wireless communication device 650according to one embodiment.

As illustrated, the wireless communication device 650 includes a firstantenna 641, a wireless personal area network (WPAN) system 651, atransceiver 652, a processor 653, a memory 654, a power management block655, a second antenna 656, and an RF front end system 657. Any of theoverload protection schemes discussed herein can be implemented in theWPAN system 651 and/or the RF front end system 657. The WPAN system 651is an RF front end system configured for processing RF signalsassociated with personal area networks (PANs). The WPAN system 651 canbe configured to transmit and receive signals associated with one ormore WPAN communication standards, such as signals associated with oneor more of Bluetooth, ZigBee, Z-Wave, Wireless USB, INSTEON, IrDA, orBody Area Network. In another embodiment, a wireless communicationdevice can include a wireless local area network (WLAN) system in placeof the illustrated WPAN system, and the WLAN system can process Wi-Fisignals.

FIG. 9B is a schematic diagram of a wireless communication device 660according to another embodiment.

The illustrated wireless communication device 660 of FIG. 9B is a deviceconfigured to communicate over a PAN. This wireless communication devicecan be relatively less complex than the wireless communication device650 of FIG. 9A. As illustrated, the wireless communication device 660includes an antenna 641, a WPAN system 651, a transceiver 662, aprocessor 653, and a memory 654. The WPAN system 660 can include an RFamplifier with an overload detection circuit in accordance with any ofthe principles and advantages discussed herein.

FIG. 9C is a schematic diagram of another example of a wirelesscommunication device 800. The wireless communication device 800 includesa baseband system 801, a transceiver 802, a front-end system 803, one ormore antennas 804, a power management system 805, a memory 806, a userinterface 807, and a battery 808.

The wireless communication device 800 can be used communicate using awide variety of communications technologies, including, but not limitedto, 2G, 3G, 4G (including LTE, LTE-Advanced, and LTE-Advanced Pro), 5G,WLAN (for instance, Wi-Fi), WPAN (for instance, Bluetooth and ZigBee),WMAN (for instance, WiMAX), and/or GPS technologies.

The transceiver 802 generates RF signals for transmission and processesincoming RF signals received from the antennas 804. It will beunderstood that various functionalities associated with the transmissionand receiving of RF signals can be achieved by one or more componentsthat are collectively represented in FIG. 9C as the transceiver 802. Inone example, separate components (for instance, separate circuits ordies) can be provided for handling certain types of RF signals.

The front-end system 803 aids in conditioning signals transmitted toand/or received from the antennas 804. In the illustrated embodiment,the front-end system 803 includes one or more power amplifiers (PAs)811, one or more low noise amplifiers (LNAs) 812, one or more filters813, one or more switches 814, and one or more duplexers 815. However,other implementations are possible.

For example, the front-end system 803 can provide a number offunctionalities, including, but not limited to, amplifying signals fortransmission, amplifying received signals, filtering signals, switchingbetween different bands, switching between different power modes,switching between transmission and receiving modes, duplexing ofsignals, multiplexing of signals (for instance, diplexing ortriplexing), or some combination thereof.

Any of the suitable combination of features disclosed herein can beimplemented in the wireless communication device 800. For example, thefront end system 803 can be implemented using any of the featuresdescribed above and/or in the sections below.

In certain implementations, the wireless communication device 800supports carrier aggregation, thereby providing flexibility to increasepeak data rates. Carrier aggregation can be used for both FrequencyDivision Duplexing (FDD) and Time Division Duplexing (TDD), and may beused to aggregate a plurality of carriers or channels. Carrieraggregation includes contiguous aggregation, in which contiguouscarriers within the same operating frequency band are aggregated.Carrier aggregation can also be non-contiguous, and can include carriersseparated in frequency within a common band or in different bands.

The antennas 804 can include antennas used for a wide variety of typesof communications. For example, the antennas 804 can include antennasfor transmitting and/or receiving signals associated with a wide varietyof frequencies and communications standards.

In certain implementations, the antennas 804 support MIMO communicationsand/or switched diversity communications. For example, MIMOcommunications use multiple antennas for communicating multiple datastreams over a single radio frequency channel. MIMO communicationsbenefit from higher signal to noise ratio, improved coding, and/orreduced signal interference due to spatial multiplexing differences ofthe radio environment. Switched diversity refers to communications inwhich a particular antenna is selected for operation at a particulartime. For example, a switch can be used to select a particular antennafrom a group of antennas based on a variety of factors, such as anobserved bit error rate and/or a signal strength indicator.

The wireless communication device 800 can operate with beamforming incertain implementations. For example, the front-end system 803 caninclude phase shifters having variable phase controlled by thetransceiver 802. Additionally, the phase shifters are controlled toprovide beam formation and directivity for transmission and/or receptionof signals using the antennas 804. For example, in the context of signaltransmission, the phases of the transmit signals provided to theantennas 804 are controlled such that radiated signals from the antennas804 combine using constructive and destructive interference to generatean aggregate transmit signal exhibiting beam-like qualities with moresignal strength propagating in a given direction. In the context ofsignal reception, the phases are controlled such that more signal energyis received when the signal is arriving to the antennas 804 from aparticular direction. In certain implementations, the antennas 804include one or more arrays of antenna elements to enhance beamforming.

The baseband system 801 is coupled to the user interface 807 tofacilitate processing of various user input and output (I/O), such asvoice and data. The baseband system 801 provides the transceiver 802with digital representations of transmit signals, which the transceiver802 processes to generate RF signals for transmission. The basebandsystem 801 also processes digital representations of received signalsprovided by the transceiver 802. As shown in FIG. 9C, the basebandsystem 801 is coupled to the memory 806 of facilitate operation of thewireless communication device 800.

The memory 806 can be used for a wide variety of purposes, such asstoring data and/or instructions to facilitate the operation of thewireless communication device 800 and/or to provide storage of userinformation.

The power management system 805 provides a number of power managementfunctions of the wireless communication device 800. In certainimplementations, the power management system 805 includes a PA supplycontrol circuit that controls the supply voltages of the poweramplifiers 811. For example, the power management system 805 can beconfigured to change the supply voltage(s) provided to one or more ofthe power amplifiers 811 to improve efficiency, such as power addedefficiency (PAE).

As shown in FIG. 9C, the power management system 805 receives a batteryvoltage from the battery 808. The battery 808 can be any suitablebattery for use in the wireless communication device 800, including, forexample, a lithium-ion battery.

One example application of the RF amplifiers herein is to enable variousobjects with wireless connectivity, such as for Internet of things(IoT). IoT refers to a network of objects or things, such as devices,vehicles, and/or other items that are embedded with electronics thatenable the objects to collect and exchange data (for instance, machineto machine communications) and/or to be remotely sensed and/orcontrolled.

The RF amplifiers herein can be used to enable wireless connectivity ofvarious objects, thereby allowing such objects to communicate in an IoTnetwork. The RF amplifiers discussed herein can be implemented in IoTapplications to enable wireless connectivity to expand the way consumersmanage information and their environment. Such RF amplifiers can enablethe new and emerging IoT applications, which can bring people and thingscloser to vital information wherever it is desired. Although IoT is oneexample application of front RF amplifiers herein, the teachings hereinare applicable to a wide range of technologies and applications. Someexample IoT applications will now be discussed.

IoT devices can be implemented in automotive systems. From telematics toinfotainment systems, lighting, remote keyless entry, collisionavoidance platforms, toll transponders, video displays, vehicle trackingtools, and the like, RF amplifiers in accordance with any suitableprinciples and advantages discussed herein can help enable convenienceand safety features for the connected vehicle.

IoT devices can be implemented in connected home environments. RFamplifiers in accordance with any suitable principles and advantagesdiscussed herein can allow homeowners greater control over their homeenvironment. IoT devices can be implemented in a host of devicesincluding smart thermostats, security systems, sensors, light switches,smoke and carbon monoxide alarms, routers, high definition televisions,gaming consoles and much more.

IoT devices can be implemented in industrial contexts. From smart cityapplications to factory automation, building controls, commercialaircraft, vehicle tracking, smart metering, LED lighting, securitycameras, and smart agriculture functions, RF amplifiers in accordancewith any suitable principles and advantages discussed herein can enablethese applications and meet specifications.

IoT devices can be implemented in machine-to-machine contexts. IoTdevices can enable machine-to-machine communications that can transformthe way organizations do business. From manufacturing automation totelemetry, remote control devices, and asset management, RF amplifiersdiscussed herein can provide cellular, short-range, and globalpositioning solutions that support a wide range of machine-to-machineapplications.

IoT devices can be implemented in medical applications. RF amplifiers inaccordance with any suitable principles and advantages discussed hereincan enable medical devices and the communication of information that isimproving the care of millions of people worldwide. RF amplifiers inaccordance with any suitable principles and advantages discussed hereincan be integrated into product designs that enable the miniaturizationof medical devices and enhance data transmission. RF amplifiers, such aspower amplifiers, in accordance with any suitable principles andadvantages discussed herein can be implemented in medical instruments.

IoT devices can be implemented in mobile devices. The communicationlandscape has changed in recent years as consumers increasingly seek tobe connected everywhere and all the time. RF amplifiers in accordancewith any suitable principles and advantages discussed herein can becompact, energy and cost efficient, meeting size and performanceconstraints, while enabling a great consumer experience. Wireless mobiledevices, such as smartphones, tablets and WLAN systems, can include oneor more RF amplifiers in accordance with any suitable principles andadvantages discussed herein.

IoT devices can be implemented in smart energy applications. Utilitycompanies are modernizing their systems using computer-based remotecontrol and automation that involves two-way communication. Somebenefits to utilities and consumers include optimized energy efficiency,leveling and load balancing on the smart grid. RF amplifiers inaccordance with any suitable principles and advantages discussed hereincan be implemented in smart meters, smart thermostats, in-home displays,ZigBee/802.15.4, Bluetooth, and Bluetooth low energy applications.

IoT devices can be implemented in wearable devices. Wearable devices,such as smartwatches, smart eyewear, fitness trackers and healthmonitors, can include RF amplifiers in accordance with any suitableprinciples and advantages discussed herein to enable relatively smallform factor solutions that consume relatively low power and enablealways on connectivity. This can allow applications to run in thebackground for lengthy periods of time without a battery recharge, forexample.

Any suitable principles and advantages discussed herein can implementedin an IoT network, IoT object, a vehicle, industrial equipment, acorresponding front end system, a corresponding circuit board, the like,or any suitable combination thereof. Some examples will now bediscussed.

FIG. 10 is a schematic diagram of one example of an IoT network 1200.The IoT network 1200 includes a smart home 1201, a smart vehicle 1202, awearable 1203, a mobile device 1204, a base station 1205, a smarthospital 1206, a smart factory 1207, and a smart satellite 1208. One ormore of the IoT-enabled objects of FIG. 10 can include a front endsystem, such as a front end module and/or front-end integrated circuit,implemented in accordance with the teachings herein.

The smart home 1201 is depicted as including a wide variety ofIoT-enabled objects, including an IoT-enabled router 1211, anIoT-enabled thermostat 1212, an IoT-enabled meter 1213, IoT-enabledlaptop 1214, and an IoT-enabled television 1215. Although variousexamples of IoT-enable objects for a smart home are shown, a smart homecan include a wide variety of IoT-enabled objects. Examples of suchIoT-enabled objects include, but are not limited to, an IoT-enabledcomputer, an IoT-enabled laptop, an IoT-enabled tablet, an IoT-enabledcomputer monitor, an IoT-enabled television, an IoT-enabled mediasystem, an IoT-enabled gaming system, an IoT-enabled camcorder, anIoT-enabled camera, an IoT-enabled modem, an IoT-enabled router, anIoT-enabled kitchen appliance, an IoT-enabled telephone, an IoT-enabledair conditioner, an IoT-enabled washer, an IoT-enabled dryer, anIoT-enabled copier, an IoT-enabled facsimile machine, an IoT-enabledscanner, an IoT-enabled printer, an IoT-enabled scale, an IoT-enabledhome assistant (for instance, a voice-controlled assistant device), anIoT-enabled security system, an IoT-enabled thermostat, an IoT-enabledsmoke detector, an IoT-enabled garage door, an IoT-enabled lock, anIoT-enabled sprinkler, an IoT-enabled water heater, and/or anIoT-enabled light.

As shown in FIG. 10, the smart vehicle 1202 also operates in the IoTnetwork 1200. The smart vehicle 1202 can include a wide variety ofIoT-enabled objects, including, but not limited to, an IoT-enabledinfotainment system, an IoT-enabled lighting system, an IoT-enabledtemperature control system, an IoT-enabled lock, an IoT-enabledignition, an IoT-enabled collision avoidance system, an IoT-enabled tolltransponder, and/or an IoT-enabled vehicle tracking system. In certainimplementations, the smart vehicle 1202 can communicate with other smartvehicles to thereby provide vehicle-to-vehicle (V2V) communications.Furthermore, in certain implementations the smart vehicle 1202 canoperate using vehicle-to-everything (V2X) communications, therebycommunicating with traffic lights, toll gates, and/or other IoT-enabledobjects.

The wearable 1203 of FIG. 10 is also IoT-enabled. Examples ofIoT-enabled wearables include, but are not limited to, an IoT-enabledwatch, an IoT-enabled eyewear, an IoT-enabled fitness tracker, and/or anIoT-enabled biometric device.

The IoT network 1200 also includes the mobile device 1204 and basestation 1205. Thus, in certain implementations user equipment (UE)and/or base stations of a cellular network can operate in an IoT networkand be IoT-enabled. Furthermore, a wide variety of IoT-enabled objectscan communication using existing network infrastructure, such ascellular infrastructure.

With continuing reference to FIG. 10, IoT is not only applicable toconsumer devices and objects, but also to other applications, such asmedical, commercial, industrial, aerospace, and/or defense applications.For example, the smart hospital 1206 can include a wide variety ofIoT-enabled medical equipment and/or the smart factory 1207 can includea wide variety of IoT-enabled industrial equipment. Furthermore,airplanes, satellites, and/or aerospace equipment can also be connectedto an IoT network. Other examples of IoT applications include, but arenot limited to, asset tracking, fleet management, digital signage, smartvending, environmental monitoring, city infrastructure (for instance,smart street lighting), toll collection, and/or point-of-sale.

Although various examples of IoT-enabled objects are illustrated in FIG.10, an IoT network can include a wide variety of types of objects.Furthermore, any number of such objects can be present in an IoTnetwork. For instance, an IoT network can include millions or billionsof IoT-enable objects or things.

IoT-enabled objects can communicate using a wide variety ofcommunication technologies, including, but not limited to, Bluetooth,ZigBee, Z-Wave, 6LowPAN, Thread, Wi-Fi, NFC, Sigfox, Neul, and/orLoRaWAN technologies. Furthermore, certain IoT-enabled objects cancommunicate using cellular infrastructure, for instance, using 2G, 3G,4G (including LTE, LTE-Advanced, and/or LTE-Advanced Pro), and/or 5Gtechnologies.

FIG. 11A is a schematic diagram of one example of an IoT-enabled watch1300. The IoT-enabled watch 1300 illustrates one example of a smartwearable that can include one or more RF amplifiers implemented inaccordance with one or more features disclosed herein.

FIG. 11B is a schematic diagram of one example of a front end system1301 for an IoT-enabled object, such as the IoT-enabled watch 1300 ofFIG. 11A. The front end system 1301 includes a first transceiver-sideswitch 1303, a second transceiver-side switch 1304, a first antenna-sideswitch 1305, a second antenna-side switch 1306, a first power amplifier1307, a second power amplifier 1308, a duplexer 1311, a directionalcoupler 1312, a termination impedance 1313, a first band selectionfilter 1315, a second band selection filter 1316, a third band selectionfilter 1317, a first LNA 1321, a second LNA 1322, and a third LNA 1323.

In the illustrated embodiment, the first transceiver-side switch 1303selects between a Band 26 transmit input pin (B26 TX IN) and a Band 13transmit input pin (B13 TX IN). The second transceiver-side switch 1303controls connection of the output of the first power amplifier 1307 tothe first band selection filter 1315 or the first band selection filter1316. Thus, the first power amplifier 1307 selectively amplifies Band 26or Band 13, in this example. Additionally, the second power amplifier1308 amplifies a Band 12 transmit input pin (B12 TX IN). After suitablefiltering by the band selection filters 1315-1317, the secondantenna-side switch 1306 selects a desired transmit signal for providingto an antenna pin (ANT) via the duplexer 1311 and the directionalcoupler 1312. As shown in FIG. 11B, the directional coupler 1312 isterminated by the termination impedance 1313. Additionally, the firstantenna-side switch 1305 provides a signal received on the antenna pin(ANT) to a desired receive output pin (four in this example) of thefront end system 1301. The illustrated front end system 1301 alsoincludes various additional pins to provide additional functionality,such as enhanced monitoring of transmit power. For instance, front endsystem 1301 includes a directional coupler output pin (CPL), andfeedback pins (B12 RX, B13 RX, and B26 RX) for providing feedbacksignals associated with transmit signals (for Band 12, Band 13, and Band26, respectively) generated by the power amplifiers. Each feedback pinincludes an LNA, in this example.

The front end system 1301 can incorporate one or more features describedin the sections herein.

FIG. 12A is a schematic diagram of one example of IoT-enabled industrialequipment 1340. In the illustrated embodiment, the IoT-enabledindustrial equipment 1340 includes heliostats 1341 for reflecting lightto a solar receiver and turbine 1342. The IoT-enabled industrialequipment 1340 can include one or more front end systems for a varietyof purposes, such as providing angular positional control of theheliostats 1341 to control concentration of solar energy directed towardthe solar receiver and turbine 1342. The IoT-enabled industrialequipment 1340 can include a front end system implemented in accordancewith one or more features disclosed herein.

FIG. 12B is a schematic diagram of another example of a front end system1345 for an IoT-enabled object, such as the IoT-enabled industrialequipment 1340 of FIG. 12A.

The front end system 1345 includes a logic control circuit 1350, atransceiver DC blocking capacitor 1351, a first antenna DC blockingcapacitor 1352, a second antenna DC blocking capacitor 1353, an LNA1354, a power amplifier 1356, an antenna-side switch 1357, a bypassswitch 1358, and a transceiver-side switch 1359.

The front end system 1345 includes control pins (CPS, CTX, CSD, ANT_SEL)for controlling the front end system 1345. The antenna-side switch 1357selectively connects either a first antenna pin (ANT1) or a secondantenna pin (ANT2) to either an output of the power amplifier 1356 orthe bypass switch 1358/input to the LNA 1354. Additionally, the bypassswitch 1358 selectively bypasses the LNA 1354. Furthermore, thetransceiver-side switch 1359 selectively connected the transceiver pin(TR) to either an input of the power amplifier 1356 or the bypass switch1358/output to the LNA 1354. The DC blocking capacitors 1351-1353 serveto provide DC blocking to provide enhanced flexibility in controllinginternal DC biasing of the front end system 1345.

The front end system 1345 can incorporate one or more features describedin the sections herein.

FIG. 13A is a schematic diagram of one example of an IoT-enabled lock1360. The IoT-enabled lock 1360 illustrates one example of anIoT-enabled object that can include a front end system implemented inaccordance with one or more features disclosed herein.

FIG. 13B is a schematic diagram of one example of a circuit board 1361for the IoT-enabled lock 1360 of FIG. 13A. The circuit board 1361includes a front end system 1362, which can incorporate one or morefeatures described in the sections herein.

FIG. 14A is a schematic diagram of one example of IoT-enabled thermostat1370. The IoT-enabled thermostat 1370 illustrates another example of anIoT-enabled object that can include a front end system implemented inaccordance with one or more features disclosed herein.

FIG. 14B is a schematic diagram of one example of a circuit board 1371for the IoT-enabled thermostat 1370 of FIG. 14A. The circuit board 1371includes a front end system 1372, which can incorporate one or morefeatures described in the sections herein.

FIG. 15A is a schematic diagram of one example of IoT-enabled light1380. The IoT-enabled light 1380 illustrates another example of anIoT-enabled object that can include a front end system implemented inaccordance with one or more features disclosed herein.

FIG. 15B is a schematic diagram of one example of a circuit board 1381for the IoT-enabled light 1380 of FIG. 15A. FIG. 15B also depicts a baseportion of the IoT-enabled light 1380 for housing the circuit board1381. The circuit board 1381 includes a front end system 1382, which canincorporate one or more features described in the sections herein.

Although FIGS. 7A-15B illustrate examples of electronic systems that caninclude an RF amplifier implemented in accordance with the teachingsherein, RF amplifier can be used in other configurations of electronics.

Applications

Some of the embodiments described above have provided examples inconnection with low noise amplifiers, front end modules and/or wirelesscommunications devices. However, the principles and advantages of theembodiments can be used for any other systems or apparatus that benefitfrom any of the circuits described herein.

For example, RF amplifiers can be included in various electronicdevices, including, but not limited to consumer electronic products,parts of the consumer electronic products, electronic test equipment,etc. Examples of the electronic devices can also include, but are notlimited to, memory chips, memory modules, circuits of optical networksor other communication networks, and disk driver circuits. The consumerelectronic products can include, but are not limited to, a mobile phone,a telephone, a television, a computer monitor, a computer, a hand-heldcomputer, a personal digital assistant (PDA), a microwave, arefrigerator, an automobile, a stereo system, a cassette recorder orplayer, a DVD player, a CD player, a VCR, an MP3 player, a radio, acamcorder, a camera, a digital camera, a portable memory chip, a washer,a dryer, a washer/dryer, a copier, a facsimile machine, a scanner, amulti-functional peripheral device, a wrist watch, a clock, etc.Further, the electronic devices can include unfinished products.

CONCLUSION

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The word “coupled”, as generally usedherein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements.Likewise, the word “connected”, as generally used herein, refers to twoor more elements that may be either directly connected, or connected byway of one or more intermediate elements. Additionally, the words“herein,” “above,” “below,” and words of similar import, when used inthis application, shall refer to this application as a whole and not toany particular portions of this application. Where the context permits,words in the above Detailed Description using the singular or pluralnumber may also include the plural or singular number respectively. Theword “or” in reference to a list of two or more items, that word coversall of the following interpretations of the word: any of the items inthe list, all of the items in the list, and any combination of the itemsin the list.

Moreover, conditional language used herein, such as, among others,“can,” “could,” “might,” “can,” “e.g.,” “for example,” “such as” and thelike, unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or states. Thus, such conditional language is notgenerally intended to imply that features, elements and/or states are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or withoutauthor input or prompting, whether these features, elements and/orstates are included or are to be performed in any particular embodiment.

The above detailed description of embodiments of the invention is notintended to be exhaustive or to limit the invention to the precise formdisclosed above. While specific embodiments of, and examples for, theinvention are described above for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize. For example, whileprocesses or blocks are presented in a given order, alternativeembodiments may perform routines having steps, or employ systems havingblocks, in a different order, and some processes or blocks may bedeleted, moved, added, subdivided, combined, and/or modified. Each ofthese processes or blocks may be implemented in a variety of differentways. Also, while processes or blocks are at times shown as beingperformed in series, these processes or blocks may instead be performedin parallel, or may be performed at different times.

The teachings of the invention provided herein can be applied to othersystems, not necessarily the system described above. The elements andacts of the various embodiments described above can be combined toprovide further embodiments.

While certain embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the disclosure. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the disclosure. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the disclosure.

What is claimed is:
 1. A radio frequency amplifier system comprising: aninput terminal configured to receive a radio frequency signal; a radiofrequency amplifier configured to amplify the radio frequency signal,the radio frequency amplifier including an amplification field-effecttransistor having a gate configured to receive the radio frequencysignal, and a degeneration circuit connected between a source of theamplifier field-effect transistor and a ground voltage; and anelectrostatic discharge protection circuit including a first pluralityof protection diodes electrically connected in series between the inputterminal and the ground voltage, and a detector having an inputconnected along an electrical path through the first plurality ofprotection diodes and an output configured to generate a detectionsignal operable to control an amount of degeneration provided by thedegeneration circuit.
 2. The radio frequency amplifier system of claim 1wherein the first plurality of protection diodes includes a firstprotection diode having an anode coupled to the ground voltage and acathode coupled to the input of the detector, and a second protectiondiode having an anode coupled to the input of the detector and a cathodecoupled to the input terminal.
 3. The radio frequency amplifier systemof claim 1 wherein the first plurality of protection diodes includes atleast three protection diodes in series between the ground voltage andthe input terminal.
 4. The radio frequency amplifier system of claim 1wherein the first plurality of protection diodes are connected in seriesfrom anode to cathode between the ground voltage and the input terminal,the electrostatic discharge protection circuit further including asecond plurality of protection diodes connected in series from anode tocathode between the input terminal and the ground voltage.
 5. The radiofrequency amplifier system of claim 1 wherein the detection signal isoperable to increase the amount of degeneration provided by thedegeneration circuit in response to the detector detecting an overloadcondition.
 6. The radio frequency amplifier system of claim 1 whereinthe radio frequency amplifier includes a capacitor connected in seriesbetween the input terminal and the gate of the amplificationfield-effect transistor.
 7. The radio frequency amplifier system ofclaim 1 wherein the degeneration circuit includes a degenerationinductor and a switch in series between the source of the amplificationfield-effect transistor and the ground voltage, and a control bufferconfigured to control the switch based on the detection signal.
 8. Theradio frequency amplifier system of claim 7 wherein the control bufferis powered by the detection signal.
 9. The radio frequency amplifiersystem of claim 8 wherein the control buffer includes an inputconfigured to receive a digital control signal for toggling the switch.10. A mobile phone comprising: an antenna configured to receive a radiofrequency signal; and a front-end system configured to receive the radiofrequency signal at an input terminal and including a radio frequencyamplifier configured to amplify the radio frequency signal, the radiofrequency amplifier including an amplification field-effect transistorhaving a gate configured to receive the radio frequency signal, and adegeneration circuit connected between a source of the amplifierfield-effect transistor and a ground voltage, the front-end systemfurther including an electrostatic discharge protection circuitincluding a first plurality of protection diodes electrically connectedin series between the input terminal and the ground voltage, and adetector having an input connected along an electrical path through thefirst plurality of protection diodes and an output configured togenerate a detection signal operable to control an amount ofdegeneration provided by the degeneration circuit.
 11. The mobile phoneof claim 10 wherein the first plurality of protection diodes includes afirst protection diode having an anode coupled to the ground voltage anda cathode coupled to the input of the detector, and a second protectiondiode having an anode coupled to the input of the detector and a cathodecoupled to the input terminal.
 12. The mobile phone of claim 10 whereinthe first plurality of protection diodes includes at least threeprotection diodes in series between the ground voltage and the inputterminal.
 13. The mobile phone of claim 10 wherein the first pluralityof protection diodes are connected in series from anode to cathodebetween the ground voltage and the input terminal, the electrostaticdischarge protection circuit further including a second plurality ofprotection diodes connected in series from anode to cathode between theinput terminal and the ground voltage.
 14. The mobile phone of claim 10wherein the degeneration circuit includes a degeneration inductor and aswitch in series between the source of the amplification field-effecttransistor and the ground voltage, and a control buffer configured tocontrol the switch based on the detection signal.
 15. The mobile phoneof claim 14 wherein the control buffer is powered by the detectionsignal.
 16. The mobile phone of claim 15 wherein the control bufferincludes an input configured to receive a digital control signal fortoggling the switch.
 17. A packaged module comprising: a packagingsubstrate; and a semiconductor die attached to the packaging substrate,the semiconductor die including an input terminal and a radio frequencyamplifier configured to amplify a radio frequency signal received fromthe input terminal, the radio frequency amplifier including anamplification field-effect transistor having a gate configured toreceive the radio frequency signal, and a degeneration circuit connectedbetween a source of the amplifier field-effect transistor and a groundvoltage, the semiconductor die further including an electrostaticdischarge protection circuit including a first plurality of protectiondiodes electrically connected in series between the input terminal andthe ground voltage, and a detector having an input connected along anelectrical path through the first plurality of protection diodes and anoutput configured to generate a detection signal operable to control anamount of degeneration provided by the degeneration circuit.
 18. Thepackaged module of claim 17 wherein the degeneration circuit includes adegeneration inductor and a switch in series between the source of theamplification field-effect transistor and the ground voltage, and acontrol buffer configured to control the switch based on the detectionsignal.
 19. The packaged module of claim 18 wherein the control bufferis powered by the detection signal.
 20. The packaged module of claim 19wherein the control buffer includes an input configured to receive adigital control signal for toggling the switch.